100% disagree. The saying "armed society is polite society" is absolutely true, at least when it comes to the interaction between arms and western social ethics. Obviously your results may vary in the Congo or Chicago or whatever.
Even if we accept the (most likely contextually false) premise that reducing firearms access for non-criminals also meaningfully reduces firearms access for criminals, I do not have any preference (ceteris paribus) between getting shot, stabbed, or having my head bashed in. In fact, I might prefer getting shot.
In the more realistic case where criminal firearm attainability is less than perfectly correlated with non-criminal firearm attainability, it makes sense for non-criminals to be armed as well.
There's also the MAD dynamic; people are less likely to physically escalate if there is a possibility of a high-severity response.
> it’s a cheap solution
A murder charge for an unjustified shooting is hardly "cheap".
I worked for a large defence contractor in the US for a number of years and got to see the contrast in professional and personal relations between their European and American employees. It’s scary when you see.